Neuropsychological studies of memory have led to a number of different distinctions in memory systems. A distinction between implicit and explicit memory is based on the type of information to be remembered (Schacter, 1987). Explicit memory is for information that has personal and temporal characteristics, can be easily accessed for verbalization, and is available to conscious awareness. Implicit memory is concerned with ruled or skill based learning, is not readily available for verbalization, and also includes the phenomenon of priming. This distinction will be assessed in individuals in age groups from the 20s through the 80s, thereby providing a finer analysis of age changes than is normally achieved. A variety of tasks thought to require implicit memory that have been developed and described in studies of normal adults and amnesic patients will be used. Subjects matched on Full Scale IQ with the WAIS-R will be tested in the following paradigms: 1) strength and/or duration of repetition priming on two word-stem completion tasks, 2) acquisition of the solution to the Tower of Hanoi puzzle, 3) acquisition of the skill of mirror-image reading, 4) acquisition of a computerized algorithm, and 5) assessment on a computerized nonverbal priming task that includes a perceptual learning component. Several tests designed to tap explicit memory will be given to subjects in all proposed studies. All subjects will also be administered 4 tests reported to assess frontal lobe function, because performance on several of the procedural memory tasks is thought to be related to frontal lobe functioning. These studies will provide an assessment of age related changes in learning and memory, an area of cognitive functioning of particular concern to middle-aged and elderly individuals, and address how different components of memory change with age and possible similarities between the memory processes of the elderly and amnesic patients.